Ejector for core drills



Jan. 14, 1947. w. B. BARR EJECTOR FOR CORE DRILLS Filed March 19, 1946 Patented Jan. 14,1947 f UNITED STAT ES PATEN T O F F 1 CE EJECTOR FOR CORE DRILLS William Bernard Barr, Clifton, N. J.

Application March 19, 1946, Serial No. 655,640

This invention relates to boring instruments, and particularly to tubular boring instruments with cutting means on one end of the tube, and means of ejecting from the tube the part that has been cut by the tube and which is lodged within the tube, and especially for ejecting said part While the tubular member is still rotating.

In the past, tubular cutters have been used and it is customary to provide a spring pressed ejector within the tubular member so that after the tubular boring instrument has cut through a material the spring ejector will force the plug from within the tubular cutter and prepare the cutter for the next cutting operation. However, with such means, in cutting fragile material the ejecting means provides the least amount of force in the initial cutting operation, whereas by the time the final cutting operation is reached the ejecting means will be compressed to provide th greatest force on the remaining skin or surface to be cut. This is detrimental with fragile material in that the ejector may cause sufficient force to break the plug from the material before the cutter has finally cut through same resulting in a ragged broken edge on one side of the material instead of a clean out. It is also apparent in the known boring instruments that the ejectors used are all formed so that the boring instrument must be stopped in order to permit a manual forcing of the ejecting means to eject the plug that has been cut.

An object of this invention is to provide a tubular boring instrument having means for ejecting the plug formed Within the tubular cutter after a cutting operation, and especially means to control the force applied to the plug to be ejected.

Another object of this invention is to provide a tubular boring instrument with manual manipulated means of ejecting the plug formed in such cutting while the boring instrument continues to rotate.

A still further object of this invention is to provide a tubular boring instrument in which the ejecting means may be used while the boring instrument is rotating and in which the amount of force applied to the plug to be ejected is controllable during the cutting operation.

Further objects may be apparent by reference to the following description and the accompanying drawing in which:

Fig. 1 illustrates a cross sectional view of the ejector applied'to a tubular boring instrument, and

Fig. 2 illustrates a cross sectional view of the 4. Claims. (01. -20) ejector, as applied to a tubular drill that is provided with diamond dust cutting means.

Referring to Fig. 1, there is illustrated a tubular boring instrument ll] comprised or. a hollow tube ll' having a cutting means at the end I 2 and provided on its upper shank with a pair of parallel slots l3, M in which a pin it: is mounted. The pin I5 is also inserted through an ejecting rod [6 which fits loosely within the tube ll so that it may be reciprocated therein. A collar H is afiixed to the tube II in any manner, such as welding, to be integral therewith and a spring l-B is mounted between the collar i1 and the pin 15 around the external periphery of the tube H. Thus, the spring l8 normally holds the ejecting rod l6 slightly above the cutting edges 12. A thrust bearing 19 is mounted around the tube El above the pin IE to bear on the pin [5, so that one portion of the bearing will rotate with the pin l5 while the other portion may be grasped by an operator.

Thus, the whole assembly (as illustrated in Fig. 1) may be operated in the following fashion. The shank of the tubular cutter ll may be mounted in a chuck (not shown) to drive the tubular boring instrument and the cutting end i2 may be applied to the material to be cut. The ejecting rod 16 may be positioned at the cutting level or above the cutting level according to the material to be cut and according to the desired pressure to be applied. To accomplish this, the pin [5 may be passed through any one of a plurality of slots in its upper end. Thus, with the ejecting rod I6 properly set the drill may be operated and as the cutting edge l2 passes through the material, the operator may manually apply a pressure to the thrust bearing H! or a pivotal arm means may be provided with a fork or other means to apply the desired pressure to the thrust bearing 19. The pressure on thrust bearing l9 will be transmitted to the pin I5 and since the pin is mounted in a pair of slots l3, l4 it may be forced downwardly against the resistance of the spring I8, and moving downwardly will move its lowermost end down against the plug cut by the cutting edges l2 and so the plug may be ejected while the tube II is rotating. This permits the operator to quickly move from one boring operation to the next without waiting to stop his drill to remove the plug that has been cut.

Referring to Fig. 2, there is illustrated a similar tubular boring instrument, except that the cutting end is provided with a glass cutting type of bit in which diamond dust cores 20 have been mounted. In this particular drill used primarily for cutting glass, it is most essential that the ejecting means be withheld from the glass plug so that a force cannot be applied to break the plug from the glass before the cutting means has cut it completely through. In this instance, the ejector may be applied to the glass plug when desired and may be applied during the operation of the drill and will not break the glass plug at any time. It will be noted in Fig. 2 that the ejector cannot place a strain on the glass plug and is entirely under the control of the operator.

It is apparent that ejectors of the type disclosed and illustrated may be applied in any form of tubular cutting means, or circular saws, and provides a controllable ejector that will not interfere with a cutting operation and will provide a desired pressure as applied by the operator. Many ramifications and changes may be made without departing from the spirit of this inven-- tion and this invention shall be limited only by the appended claims.

What is claimed is:

1. A boring instrument including a shank part provided with an axial bore, a tubular cutter affixed to the hollow end of said shank, an ejectin rod slidable in the axial bore, two parallel slots in the shank at the upper end of the axial bore, a pin passed through said parallel slots and said ejecting rod at its upper end to slidably hold said ejector within the axial bore, resilient means mounted between said pin and the lower'end of said shank to hold said ejector in a retracted position, and rotatable means mounted around said shank to bear on said pin to operate said ejecting means.

2. A boring instrument including a shank part provided with an axial bore, a tubular cutter having diamond dust bonded pins mounted in the cutting end thereof, an ejecting rod slidably mounted in the axial bore, two parallel slots in the shank at the upper end of the axial bore, a

pin passed through said parallel slots and said ejecting rod at its upper end to slidably hold said ejector within the axial bore, resilient means mounted between said pin and diamond dust cutting means at the lower end of said shank to hold said ejector in a retracted position, and rotatable means mounted around said shank to bear on said pin to operate said ejecting means.

3. A drilling tool including a stem formed tubular at one end and provided with a cutting edge, a rod slidably mounted in said tubular end, said tubular shank of said stem having a pair of parallel axially extending slots formed therein, a pin projecting diametrically outwardly from the periphery of said rod and engaging in said slots, a cutting means carried on the end of said tubular member, resilient means mounted between said pin and the cutting end of said tubular stem to retain said rod within the tubular stem, a bearing embracing said stem and resting on the diametrically positioned pin, means to apply a force to the ejecting rod to eject the material cut during the rotation of the tubular cutter.

4. A drilling tool including a stem formed tubular at one end and provided with a cutting edge, a rod slidably mounted in said tubular end, said tubular shank of said stem having a pair of parallel axially extending slots formed therein, a pin projecting diametrically outwardly from the periphery of said rod and engaging in said slots, said pin extending beyond the periphery of said stem to support a bearing thereon, a cutting means carried on the end of said tubular member, resilient means mounted between said pin and the cutting end of said tubular stem to retain said rod within the tubular stem, said bearing embracing said stem and resting on the diametrically positioned pin, means to apply a predetermined force to the ejecting rod to eject the material cut during the rotation of the tubular cutter.

WILLIAM BERNARD BARR. 

